The present invention relates to a tremolo unit for an electric guitar, and more particularly relates to improvement in function of a combine fixing type tremolo unit used for electric guitars.
In the following descriptions, the term "string direction" refers to the running direction of a string in a stretched state on the body of an electric guitar.
In the general construction of an electric guitar, each string is fixed under tension at one end to a pin secured to the main body of the guitar and, at the other end, to a tremolo unit mounted to the main body at a location remote from the pin in the string direction. As well known, such a tremolo unit is used for causing high speed cyclic change in string tension, thereby providing unique, colourful acoustic effects. More specifically. a tremolo unit includes a bridge base mounted in a swingable arrangement to the main body and a bridge mounted atop the bridge base in on arrangement movable substantially in the string direction. The bridge is provided with a string hole for passage of the associated string.
Depending on the manner of fixing of a string conventional tremolo units are classified into two major groups, i.e. a direct fixing type and on indirect fixing type.
In the case of the direct fixing type, a string bead generally attached to the free end of each string is removed and the string received in the string hole of the bridge is pressed against the wall of the string hole for fixation. One typical example of this direct fixing type is called a Froidrose type, which has no function of octave adjustment. This tremolo unit includes a lock bolt screwed into the bridge in order to press an associated string against the wall of the string hole in the bridge. This lock bolt is accompanied with a fine adjustment screw which adjust the extent of string pressing by the lock bolt.
Such a simple pressing by the lock bolt only is liable to allow uncontrolled slippage and resultant slack of the string. In addition, repeated and frequent application of pressure to a string in the base range tends to damage the coiled structure of the string. Further, the lock bolt is provided with a head of a larger diameter for manual operation. When the lock bolt is screwed into the bridge to press the string in the string hole. movement of the lock bolt may be barred by contact of its enlarged head with the fine adjustment screw. In order to obviate this trouble, the lock bolt is required to have a large length. Such an elongated construction mars compactness of the tremolo unit.
In the case of the indirect fixing type, a string is locked to the bridge of a tremolo unit via the above-described string bead. Examples of this type are proposed in Japanese Utility Model Openings Sho.60-189097, Sho.61-19629 and Sho.62-140593. A bridge used for this indirect fixing type is in general very complicated in construction and, as a consequence, by means of die cast process using non-iron-type metal such as zinc. A bridge made of non-iron-type metal tends to facilitate damping of string vibration and, as a consequence, seriously deteriorate tone colour.